ELASTOMER-ELASTOMER AUTOHESION-INTERPHASE GRADIENT OF ELASTIC MODULUS

The effect of migration on the vulcanizing ingredients is considered when two sheets of carbon black reinforced0 polyisoprene are brought into contact. Two formulations (conventional and efficient ones) are chosen. The formation of macroscopic interphases on both sides of the interface is shown by measurements of local modulus by microindentation. The local concentration of sulfur is determined by energy dispersive X-ray analysis. Near the interface, the modulus is always higher than in the hulk of the sheets although the interfacial strength may be quite low. Co-crosslinking of the chains in the interphase at the molecular level and macroscopic thick interphases arc two important. aspects of elastomer-elastomer joints.